China faces growing threats from invasive alien species

Giant African snails happily munch on vegetables in south China, one bite from a red fire ant from Latin America causes humans to slip in to a coma and the ecosystem in northwest China is under threat from invasive trees from Central Asia.

As China grapples to cope with the adverse affects of an influx of non-native species, either deliberately or accidently introduced, experts are calling for specific laws and regulations to control their uncontrolled spread.

Of the 100 most threatening invasive species in the world, 51 have been found in China, according to the fourth National Seminar on Biological Invasion, which was held this week in Nanning, capital of south China's Guangxi Zhuang Autonomous Region.

These non-indigenous species have swallowed swathes of forests. More than 40 million trees die as a result of insects annually, two thirds of this are reportedly due to non-native species.

Imported hazardous species are on the rise. According to Zhao Shucong, head of China's national forestry bureau, Chinese customs only intercepted 500 batches of foreign pests in 2000. In 2013, this number skyrocketed to 610,000.

Last century, 25 invasive foreign species were recorded to have made their way into China. In comparison, in the past 14 years alone, experts have already found 13 new species.

"In the decade before 2004, only one or two invasive species were found, but in the past ten years, we have discovered at least one new non-native species each year," said Liu Wanxue, an expert on biological invasion at the Chinese Academy of Agricultural Sciences.

With China's opening-up policy, and the increasing exchanges of personnel and goods it facilitated, more non-native species are likely to enter the country, particularly via our border areas, Liu said.

These introduced species have also discovered ingenious ways to migrate across China, such as via the south-to-north water diversion project and its series of canals and pipelines, said Xie Songguang, a research fellow with the Chinese Academy of Sciences' Institute of Hydrobiology.

The east route of the diversion project, which connects the Yangtze River, the Huaihe River and the myriad waterways along the way, provides a fertile route for the spread of non-native species, such as Cabomba caroliniana, a type of water grass originating from Latin America, Xie said.

In 2010, Xie found that the highly invasive Cabomba caroliniana, which was largely found in the lower reaches of the Yangtze River, was spreading toward north China.

Xie said the water diversion project may also facilitate the migration of 72 kinds of non-indigenous exotic fish to more regions.

That has also raised concerns about the latest phase of the project, the middle route, which kicked off last Friday.

As calls for change become increasingly more urgent, experts have suggested measures to address the situation.

Lu Yongyue, a professor with the South China Agricultural University, said regional prevention and control would be key.

"Take red imported fire ants. It is impossible to eliminate them currently, but we can confine and kill them in some areas to minimize the damage they cause," Lu said.

It is important to get to the root of the problem, and stop foreign species from entering China, said Liu Wanxue.

"China currently does not have specific laws and regulations regarding the invasion of alien species, so how can it be prevented and controlled?" Liu said.

China has issued a list of harmful agriculture and forestry pests, but technical shortcomings in inspection and quarantine processes remain, Liu added.

"It is necessary for China to come up with a comprehensive warning mechanism to stop them entering the country," he said.